Rheostat



July 17, 1928.-

w. E. NEWMAN RHEdsTAT Filed Dec 27, 1926 INVENTOR 7 WILL/AMI 5 ,NEWMAN ATTORNE Patented July 17, 1928.

ITED STATES PATENT oFFIcE;

WILLIAM EDWARD NEWMAN, or tITICA, NEW YORK.

RHEOSTAT.

Application filed December 27, 1332s. Serial No. 157,113.v

.This invention relates to improvements in rheo'stats and has for one of its objects, the

securing of a large contact surface, between the wire of the resistance unit and the movable contact element.

Another object of my 'invention i's to provide a rheostat which reduces to a minimum the amount of weal-between the'friction surfaces,

Another object of my invention is to pro;

vide a rheostat which is quiet in its operation, and a still further object of my invention is to provide arheost-at in which the contact surface"v between the movable element and the resistance unit is self-align ing andin whichmeans is provided to take up irregularities in manufacture.

- Other objects will be' observed as the description progresses.

with a hub portion 2, around which'is dis' posed a metallic band 3, which is preferably made of anygood conducting material, and the same may be plated with silver or other metal, or allo to insure a good contact as the band 3 is brought into engagement with the turns 4 wound on a suitable insulator 5. The resistance unit comprising thewire 4 and insulator 5 is preferably rectangular in shape and positioned. edgewise in a groove in the base 1, being held therein 1n any satisfactory manner. The band 3, is held in position on the hub 2 as b means of a screw 6. Passing through and astened to'the base 1 is a sleeve 7. An operating shaft 8 is held in the sleeve-7 by a snap lock ring 9 which fits in a groove in the shaft 8. Carried on the end of the .shaft 8 is a contact arm or lever 10, which has enlargementsor guides 11 adj acent the turned over end 12, on which rests the band, 3. The arm or lever 10 is provided with a loop 13, which provides an automatic take-up or gives a'resilient pressure between the band 3 and the resistance wire 4 soithat a good contact is alwaysinsured. between the band and the resistance Wire 4. Oneend of the resistance wire 4 extends closely adjacent, and 'is connected to a terminal post 14, while the other end is f anchored to the insulator 5.- The contact band "3 is joined byto the terminal post, ometer circuit is completed,'-for example, from the terminal post 14 to the wire 4, band 3, connector strap 15 to terminal post 16. A pair of stops 17 are provided to engage the arm 10, as the same is' turned by the shaft-8. The'r'heostat may be mounted blymeans of screws or studs passing through holes 18 or the rheostat may be mounted by means of'a' nut 19 engaging the'threaded end of the sleeve- 7, by the flange on the nut 19 engaging the mounting panel. From the preceding description it will be readil understood that as the shaft .8 is turne that the end 1201* the contact arm 10 slides under the contact band 3 and the band is rolled into contact with the convolutions of the resistance wire 4. This action gives a very smooth, eas and quiet operating rheostat, and. a goo contact is insured through the means of loop 13 as heretofore described. v

Since the band 3 engages the resistance wireonthe long portion of a plurality of turns, considerable current may be carriedthrough the rheostat without overheatingthe contact and due to the construction heretofore described any slight longitudinal movement of 'theshaft in the sleeve 7 is compensated for as the band is more or less self aligning over the end of the'contact arm.

- It will be obvious that changes may be made 'in the details of my invention without departing from the spirit of the same, and

the scope of the appended claims.

Having'thus described my invention,-what I claim is:

1. A rheostat comprising a base, a shaft rotatably carried by the baseand extending therethrough, a resistance unit consisting of an insulator and wire wound thereon arouately carried on the base in radially spaced, relation to the axis ofthe' shaft, a one piece arm carried on the end of the shaft and exthe connector strap 15 1.6, so that a potenti-,

tending toithe resistance unit and a contact band anchored on the base and extending between the end of the arm and the turns of the resistance wire whereby as the arm is moved the bandisrolled into contact with the wire,

to the huh and passing over arm into contact with said turns of resistance said arm being previded with integral means comprising a flexihie loop for putting a resii' ient pressure onsaid contact hand.

EZQ'A rheostat comprising a, base, a shaiit rotatahiy carried by the base and extending therethrough, a resistance unit consisting of an insulator and wire wound thereon arcuately carried onthe base in radially spaced relation to the axis of the shaft said base having a hub portion around the shaft and a metallic band disposed around and fastened the end'oft the wire whereby as the arm is turned the band is rolled into contact with the turns of Wire and means associated with the arm for obanceunit, said arm having iateraiiy extending guide fingers, said base having a huh portion around the shaft and a metallic band disposed around and fastened to the hub and passing over the endoii the arm back o'tthe guide fingers into contact with-said turns of wire as and for the purposes described and pressure take up means inciruded 'with the V a. A rheostat comprising a'base, an operating member carried by theba'se, a resistance unit also carried-by the base a flexible contact member Without free ends anchored to the base but very'lcoseiy fitting around 'a taining a resilient pressure between the band and the resistance wire. 3. A rheostat comprising a base, a shaft rotatably carried by the base and extending. therethrough, a resistance uni-t consisting 0 an insulator and wire wound thereon arouately carried on the base in radially spaced relation to the axis of the shaft, an arm carried by the shaft and extending to the-resist-v' .part of the base, but adapted to have differ ent parts thereof brought successively into engagement with the resistance unit and means acting between the operating. member and the flexible contact member for moving ditferent part-s thereof'into Contactjwith the resistance unit-.- r

, In testimony whereof, I afiix my signa ture.

WiLLIA'M EDWARD NEWMAN. 

